Putting A Cheapo 1800W DC-DC Boost Converter To The Test

January 1, 2026 by 2 Comments

These days ready-to-use DC-DC converters are everywhere, with some of the cheaper ones even being safe to use without an immediate risk to life and limb(s). This piques one’s curiosity when browsing various online shopping platforms that are quite literally flooded with e.g. QS-4884CCCV-1800W clones of a DC-DC boost converter. Do they really manage 1800 Watt even without active cooling? Are they perhaps a good deal? These were some of the questions that [Josh] over at the [Signal Drift] channel set out to answer.

The only real ‘datasheet’ for this module seems to come courtesy of a Floridian company who also calls it the 36843-PS, but it features specifications that are repeated across store listings so it might as well by the official ‘datasheet’. This module is marketed as being designed for the charging of lead-acid and similar batteries, including the boosting of PV solar panel outputs, though you’d really want to use an MPPT charger for that.

With this use case in mind, it’s probably no surprise to see on the oscilloscope shots under load that it has a tragic 100 kHz switching frequency and a peak-to-peak noise on the output of somewhere between 1-7 VDC depending on the load. Clearly this output voltage was not meant for delicate electronics.

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Welded frame and cylinders for T1 #5550

Building A Steam Loco These Days Is Nothing But Hacks

January 1, 2026 by 7 Comments

The Pennsylvania Railroad (PRR)’s T1 class is famous for many reasons: being enormous, being a duplex, possibly having beaten Mallard’s speed record while no one was looking… and being in production in the 21st century. That last fact is down to the redoubtable work by the PRR T1 Steam Locomotive Trust, who continued their efforts to reproduce an example of these remarkable and lamentably unpreserved locomotives in the year 2025.

They say that 2025 was “the year of the frame” because the frame was finally put together. We might say that for the PRR Trust, this was the year of welding. Back when the Baldwin and Altoona works were turning out the originals, the frames for steam locomotives were cast, not welded. There might not be anywhere on Earth to get a 64′ long (19.5 m), 71,000 lbs steel casting made these days. Building it up with welded steel might not be perfectly accurate, but it’s the sort of hack that’s needed to keep the project moving.

The cylinders, too, would have been bored-out castings back the day. Getting the four (it’s a duplex, remember) assemblies cast as one piece didn’t prove practical, so T1 #5550 will have welded cylinders as well. Given modern welding, we expect no problem with holding steam pressure. The parts are mostly machined and will be welded-together next year.

The giant wheels of the locomotive have been cast, but need to be machined. It’s not impossible to believe that locomotive #5550 will be on its frame, on its wheels, in 2026. The boiler is already done and the injectors to get water into it have been reinvented, which can perhaps be considered another hack. Continue reading “Building A Steam Loco These Days Is Nothing But Hacks” →

A giant pokeball is the best place to hide this holiday season.

Our New Years Wish Is To Hide In A Giant Pokéball

January 1, 2026 by 2 Comments

Between the news, the world situation, and the inevitable family stresses that come this time of year, well — one could be excused for feeling a certain amount of envy for those adorable pocket monsters who spend their time hidden away in red-and-white orbs. [carlos3dprint] evidently did, but he didn’t just dream of cozy concave solitude: he made it happen, with 3D printing and way too much post-processing.

Arguably 3D printing is not the ideal technique for such a large build, and even [carlos], despite the 3dprint in his handle, recognized this: the base frame of the sphere is CNC-routed plywood. He tried to use Styrofoam to make a skin, but evidently he’d lost access to the large CNC cutter he’d borrowed for the plywood frame at that point, as he was trying to do the cuts by hand. It still seems like it wouldn’t have be any worse than the little printed blocks from four different printers he eventually hot-stapled into a shell.

We only say that because based on his description of how much resin and filler went into creating a smooth outer surface on his Pokéball, the raw surface of the prints must have been pretty bad before fiberglass was applied. Still, it’s hard to argue with results, and the results are smooth, shiny and beautiful after all the sanding and painting. Could another technique have been easier? Maybe, but we hack with what we have, and [carlos] had 3D printers and knows how to make the best of them.

The interior of the ball is just large enough for a cozy little gaming nook, and no guesses what [carlos] is playing inside. The Instructable linked above doesn’t have many interior photos, though, so you’ll have to check the video (embedded below) for the interior fitting out, or jump to the tour at about the 15 minute mark.

Given ongoing concerns about VOCs from 3D printers, we kind of hope the Bulbsaur-themed printer he’s got in there is decorative, but it’s sure a nice homage to the construction method. Other pokeballs featured on Hackaday have been much smaller, but we’ve always had a soft spot for scaled-up projects.

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The Cutting Truth About Variable Capacitors

January 1, 2026 by 3 Comments

If you’ve seen a big air-variable capacitor, you may have noticed that some of the plates may have slots cut into them. Why? [Mr Carlson] has the answer in the video below. The short answer: you can bend the tabs formed by the slots to increase or decrease the capacitance by tiny amounts for the purpose of tuning.

For example, if you have a radio receiver with a dial, you can adjust the capacitor to make certain spots on the dial have an exact frequency. Obviously, you can only adjust in bands depending on how many slots are in the capacitor. Sometimes the adjustments aren’t setting the oscillator’s frequency. For example, the Delco radio he shows uses the capacitor to peak the tuning at the specified frequency.

You usually only find the slots on the end plates and, as you can see in the video, not all capacitors have the slots. Of course, bending the plates with or without slots will make things change. Just don’t bend enough to short to an adjacent plate or the fixed plates when the capacitor meshes.

Of course, not all variable capacitors have this same design. We’ve seen a lot of strange set ups.

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Jon Peddie’s The Graphics Chip Chronicles On Graphics Controller History

January 1, 2026 by 10 Comments

Using computers that feature a high-resolution, full-color graphical interface is commonplace today, but it took a lot of effort and ingenuity to get to this point. This long history is the topic of [Dr. Jon Peddie]’s article series called The Graphics Chip Chronicles. In the first of eight volumes, the early days of the NEC µPD7220 and the burgeoning IBM PC.

Texas Instruments TMS34020 (Source: Wikimedia)
Texas Instruments TMS34020 (Source: Wikimedia)

These are just brief overviews of these particular chips, of course, with a lot more detail to be found when you go digging. Details such as the NEC µPD7220 being the graphics chip in Japan’s PC-9800 series of computers which are famous for the amazingly creative art and games that this chip enabled.

While the average Hackaday reader is likely familiar with the IBM PC side of things, Texas Instruments’ graphics controllers, including the very interesting TMS34010 and successor TMS34020 which can be called the first proper graphical processing units, or GPUs, effectively a CPU with graphics-specific instructions.

Although it’s tempting to see computer graphics as a direct line from the days of monochrome graphic controllers to what we have today in our PCs, there were a lot of companies and countless talented individuals involved, including companies who built clones that would go on to set new standards. If you’re into reading through a few years worth of computer history articles by someone who has been in the industry for even longer, it’s definitely worth a read.

Thanks to [JohnS_AZ] for the tip.

Top image: NEC µPD7220 by Drahtlos – Own work, CC BY-SA 4.0)

Trace Tracing To The Tunes

January 1, 2026 by 10 Comments

Some kind of continuity beeper has been a standard piece of gear since the dawn of electronics. Sure, you probably have an ohm meter, but sometimes you don’t care about the actual resistance. You just want to know whether something connects or doesn’t, especially with a PCB trace or a cable. But what if your beeper could tell you more? [Nick Cornford] asks and answers that question with a beeper that lets you estimate resistance via pitch.

The circuit is relatively simple. A short to ground causes a voltage divider to produce a fraction of the battery voltage and a FET to conduct that fractional voltage to a VCO via a high-gain amplifier. The VCO converts voltage to frequency, and an audio amplifier feeds it to the speakers.

The two amplifiers and the VCO require two dual op-amp chips. The original schematic sends the output to some relatively high-impedance headphones. To drive more practical ones, the circuit can drop one op amp and use another FET and a separate battery.

Of course, you have many design choices, especially for the audio amplification. There are plenty of VCO circuits, or you could probably substitute a small microcontroller with an A/D converter and PWM output. Yes, you can also make a VCO with a 555.

VCOs are common because they are at the heart of PLLs.

The Many-Sprites Interpretation Of Amiga Mechanics

December 31, 2025 by 13 Comments

The invention of sprites triggered a major shift in video game design, enabling games with independent moving objects and richer graphics despite the limitations of early video gaming hardware. As a result, hardware design was specifically built to manipulate sprites, and generally as new generations of hardware were produced the number of sprites a system could produce went up. But [Coding Secrets], who published games for the Commodore Amiga, used an interesting method to get this system to produce far more sprites at a single time than the hardware claimed to support.

This hack is demonstrated with [Coding Secrets]’s first published game on the Amiga, Leander. Normally the Amiga can only display up to eight sprites at once, but there is a coprocessor in the computer that allows for re-drawing sprites in different areas of the screen. It can wait for certain vertical and horizontal line positions and then execute certain instructions. This doesn’t allow unlimited sprites to be displayed, but as long as only eight are displayed on any given line the effect is similar. [Coding Secrets] used this trick to display the information bar with sprites, as well as many backgrounds, all simultaneously with the characters and enemies we’d normally recognize as sprites.

Of course, using built-in hardware to do something the computer was designed to do isn’t necessarily a hack, but it does demonstrate how intimate knowledge of the system could result in a much more in-depth and immersive experience even on hardware that was otherwise limited. It also wasn’t free to use this coprocessor; it stole processing time away from other tasks the game might otherwise have to perform, so it did take finesse as well. We’ve seen similar programming feats in other gaming projects like this one which gets Tetris running with only 1000 lines of code.

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